A researcher decides to run an experiment to study the effects of two independent variables on learning. (1) She will vary background noise by playing or not playing a radio while subjects study a list of words. (2) She will vary the length of the list to be learned: Half the subjects will try to learn a short list; half will try to learn a long list in the same amount of time. The dependent variable is the percentage of words recalled. Take this hypothetical experiment and do the following:

a. Describe this experiment using shorthand notation for factorial designs.

b. Diagram the experiment using a design matrix.

c. Identify three extraneous variables you think might affect the outcome of this study.